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प्रश्न
Describe the oxidising action of potassium dichromate and write the ionic equation for its reaction with H2S.
उत्तर
Potassium dichromate acts as a strong oxidizing agent. It is used as a primary standard in volumetric analysis. The oxidation action of dichromate ion in an acidic medium can be represented as follows –
\[\ce{Cr2O^{2-}_7 + 14H^+ + 6e^- -> 2Cr^{3+} + 7H2O}\] (E– = 1.33 V)
H2S is oxidised to sulphur.
\[\ce{Cr2O^{2-}_7 + 8H^+ + 3H2S -> 2Cr^{3+} + 7H2O + 3S}\]
संबंधित प्रश्न
What are the characteristics of the transition elements and why are they called transition elements?
The paramagnetic character in-3d-transition series elements increases-: up to Mn and then decreases.
Two metallic elements A and B have the following standard oxidation potentials: A = 0·40v B = - 0·80v. What would you expect if element A was added to an aqueous salt solution of element B? Give a reason for your answer.
Maximum oxidation state is shown by ____________.
Which of the following will not act as oxidising agents?
(i) \[\ce{CrO3}\]
(ii) \[\ce{MoO3}\]
(iii) \[\ce{WO3}\]
(iv) \[\ce{CrO^{2-}4}\]
Why first ionisation enthalpy of Cr is lower than that of Zn?
Mercury is the only metal liquid at room temperature due to its:-
Give reason for the following statement:
Physical and chemical properties of the 4d and 5d series of the transition elements are quite similar to expected.
Write the number of unpaired electrons in Cr3+.
(Atomic number of Cr = 24)
Explain the magnetic properties of d-block (or transition) elements.
